<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>unset</title>
    <style type="text/css">
        .father{color: red;border: 1px solid black}
        .children{color: green;border: 1px solid blue}
        .unset{color: unset;border: unset}
        .father1{position: relative;width: 320px;height: 200px;color: red;border: 1px solid black;background-color: darkgray}
        .block{width: 80px;height: 80px;background-color: brown;color: #fff;position: absolute;top: 60px;right: 0}
        .left-block{left: 0}
      /*  .right-block{right: 0}*/
    </style>
</head>
<body>
    <div class="father">
        <div class="children">第一个元素</div>
        <div class="children unset">第二个元素</div>


    </div>
<div class="father1">
    <span class="block left-block">左模块</span>
    <span class="block right-block">右模块</span>
</div>
</body>
</html>